Interview by Julian Baggini

Philosophers imploring the rest of the world to pay more attention to them will often say in chorus that the questions they deal with are of fundamental and profound interest to any reflective person. True, but that doesn't clinch their case. Philosophy as we know it is a combination of this perennial subject matter and a particular type of reasoned approach to it. But others tackle the same questions in different ways, ways which are perhaps more fruitful for the non-academic.

Novelists are a case in point, of which Salley Vickers is a particularly interesting example. Vickers has written four novels which touch on big philosophical themes of ethics, reality, religion and death. But they are very much philosophical novels, not treatises with plots grafted on.

Vickers's own interest in philosophy goes back a long way. “I thought quite seriously about reading Moral Sciences when I was at Cambridge,” she told me when we met near her west London home. “I read English but did a paper called the English Moralists and I read various philosophers for that.”

And her reading has featured philosophers ever since. Over the course of our conversation she reveals that she has read “quite a lot of Plato”, and that her understanding of the nature of reality has been informed by Thomas Nagel and Stanley Cavell. She also expresses her admiration for David Hume's scepticism and work on induction. “I think he understands humanity incredibly well,” she says. “He's a remarkably good psychologist. I think he had a very refined sense of what philosophy couldn't handle, and I like that. There's a sort of mix of confidence and humility in his work.”

This fascination for what philosophy can't handle is perhaps what gives literature in general and Vickers in particular a distinct role in the exploration of philosophical problems. In her latest, and to my mind best, novel, The Other Side of You , her narrator, a psychiatrist, quotes the line of Harold Pinter: “Apart from the known and the unknown, what is there?”

“At first he thinks that's a very smart remark,” Vickers explains, “but later he comes to think that everything interesting is what happens between the known and the unknown, and I suppose I think that too. That's what my novels are about.”

The same idea of investigating the grey areas emerges in Mr Golightly's Holiday , where the eponymous protagonist remarks that the important things in life stand outside of reason.

“Because he's a man of such clear ideas, he makes the mistake of imagining that when ideas are not clear, that there isn't something necessarily to be discovered. I do think there's a lot of unclarity in the world, and it's not necessarily best dealt with by analytic philosophy, but I don't think that means it's not a subject for philosophy.

“The actual demarcation of what can and can't be known is a subject for philosophy but philosophy doesn't always have the tools in itself to discover what happens beyond that demarcation.”

That's perhaps why Vickers's favourite philosophical observation is that “Socrates is the wisest of men because he knows that he doesn't know.”

Of all the unclarities literature can deal with, perhaps it is best equipped to handle the moral ones.

“I think the way in which literature is relevant to ethics is that in a real novel, one that's got living people and ideas in it, you can actually encounter beings which are not human but which have all the attributes of being human, and observe all the consequences of their actions. You don't actually know the outcomes when you put your characters together, so it probably is a version of a thought experiment. You can never do that ethically in life.

“I think what's remarkable about Crime and Punishment is that Raskolnikov commits the moral transgression for us, without us having to do it, and yet we feel utterly the consequences almost as if we had done the moral transgression ourselves. It's practical ethics as opposed to conceptual ethics because the practical side is: the characters enact the moral choices. They aren't actually flesh and blood human beings, but you have all the emotional reactions that you have with real human beings.”

One consequence of this is that literature is more sensitive to “moral nuances” than philosophy. For instance, in Vickers's novels, some of the characters behave in ways the rules say they shouldn't, yet part of what her storytelling does is to make us more forgiving. When you make morality more flesh and blood you become less doctrinaire. Also, as she observes, your “ethical priorities” change, with “probably forgiveness and mercy” more to the fore.

These have, of course, been more the terrain of religion than philosophy. Concepts like that of mercy do not feature highly in the moral systems of Mill and Kant, for example.

“No it doesn't and that's where I think religion has it over philosophy. And I do believe human beings have a religious dimension. It's no good just saying we're not going to be religious because plenty of other people are, so I think we have to include the religious dimension even if it's to say ‘I'm not a member of an organised religion'.

“You'll also find that a lot of great scientists accept the religious dimension, Einstein, for example. A lot of contemporary physicists, when they're talking about the structure of the universe and the structure of reality, include the notion of God. Particularly among physicists and mathematicians you get a greater tolerance of religion. I call it a metaphysical dimension, actually, rather than religious. I think of myself as a metaphysical writer rather than a religious one.”

You might think from such comments that Vickers was herself religious, an impression superficial readers may find reinforced by the ghosts and angels that feature in her novels. But that would be too crude a characterisation. Vickers is relatively indifferent to questions of creed, and whether or not a God actually exists. For her, the reality of the religious dimension does not equate to the reality of an omnipotent God or a literal afterlife.

“I believe that all the characteristics which appear throughout human cultures are related to some objective reality. We have eyes because something's out there, we have ears because something's out there. You don't get cultures without religion, and I think the religious dimension is there because it's registering some important objective reality, But it's quite a difficult thing to define, and I wouldn't like to define it as God, although God could be a shorthand for it, for the creative principle.”

Perhaps one way of understanding this is that, just as the known and the unknown do not exhaust all reality, neither do the natural and the supernatural. You don't need to believe in gods and angels to believe that a purely naturalistic account of the world leaves things out. This belief in the limitations of naturalism is evident in her characterisation of realist fiction.

“A lot of modern novels make the mistake of confusing realism and naturalism, and think that if they want to be realist they have to talk about contemporary issues, like child abuse. I think mine are realist novels, they're not naturalistic novels, and I'm very keen on that distinction which has been lost. Kafka's ‘Metamorphosis' is a realist story, but it's not a naturalistic one. It's not really credible to imagine that I would wake up one morning and be a beetle, but it's entirely realistic.”

Of course, the nature of reality is another philosophical issue that interests Vickers.

“What about Hamlet? It seems to me that there's an important sense in which Hamlet is real. Of course, he was never born, although Hamlet dies, and he has many of the attributes of a living human being. And he's real, we know a lot about him, in many ways he's more real than you and I are. Hamlet has had more impact on me than many people I have met and known.”

But perhaps the theme that Vickers has grappled with most is death. “I don't actually believe in ghosts or angels, but I think both are useful, traditional images for intangible reality, and one of the intangible realities is the continuation after death of our consciousnesses in quite powerful ways.” Not a continuation of souls, but in the minds of others we have known.

This idea is actually very close to that of Derek Parfit, who famously argued that personal identity is simply a matter of connections and continuities between psychological states. Once identity is understood in this way, Parfit argued that the differences between self and other become less absolute, and so death too becomes less of an abrupt end.

This perhaps illustrates a typical difference between how novelists and philosophers deal with the same issues. The philosopher takes an analytic approach and tries to give as clear and reasoned account of a phenomenon as possible. Novelists prefer to run with ideas and explore their impacts on human characters. It is therefore not surprising if the words of the latter sell more than those of the former, as they speak more directly to people's lived experiences.

But that does not mean novelists are irrational flakes. “I think reason is powerful and important and I wouldn't want to do without it,” Vickers claims. And indeed, none of her novels could have done without it either.

The Other Side of You is published by Fourth Estate

See www.salleyvickers.com